import java.awt.Graphics;
import javax.swing.JPanel;

public class PanelDibujo extends JPanel{
 
    public void paintComponent( Graphics g)
    {
        super.paintComponent(g);
        
        int anchura = getWidth();
        int altura = getHeight();
        
        g.drawLine(0, 0, anchura, altura);
        
        g.drawLine(0, altura, anchura, 0);
    }
}
